.mainCanvas{padding: 10px;}
#monaco{height: 100px;width: 500px;}
[data-drag="ace-drag"]{
    outline: 1px solid #aaa;
}
[data-drag="ace-drag"]:hover{outline: 1px dashed #1890ff;}

[data-postion="beforeSelect"]{
    position: relative;
}
[data-postion="beforeSelect"]::after{
content: " ";
position: absolute;
border-left: 3px solid #1890ff;
height:100%;left:-3px;top: 0;
}
[data-postion="afterSelect"]{
    position: relative;
}
[data-postion="afterSelect"]::after{
    content: " ";
    position: absolute;
    border-right: 3px solid #1890ff;
    height:100%;right: -3px;top: 0;
    }
[data-drag="select"]{
    outline: 1px solid #1890ff;
}